This is planned on being fixed in the next version of ECMAScript (which will be available via an opt-in). It will result in typeof null === 'null'.
Note: it's been rejected
Bill Gates and Marc Andreessen die and go to heaven. God meets them and announces that they will get stabbed with a needle for each major bug in their browser software.
First it's Marc's Turn: "In Navigator 1.0 there was a big security hole" DOUCHE! "In Navigator 1.1 you couldn't empty the cache" DOUCHE! Marc rubs his butt and looks around: "Where did Bill go?" God says in reply: "He's just being clamped into the sewing machine..."